Underwater well completions



Nov. 21, 1967 a. H. NELSON ET AL 3,353,595

UNDERWATER WELL COMPLETIONS Filed May 22. 1964 5 Sheets-Sheet l BY 134 5mg Nov. 21, 1967 B. H. NELSON ET AL UNDERWATER WELL COMPLETIONS Filed May 22, 1964 Zia 5 Sheets-Sheet 2 Eoby A. /Ve/Jo/7 INVENTORJ VBY ATTOIFA/EVJ Nov. 21, 1967 B. H. NELSON ET AL 3,353,595

UNDERWATER WELL COMPLETI ONS 5 Sheets-Sheet 4' Filed May 22. 1964 2 67 INVENTORJ Nov. 21, 1967 a. H. NELSON ET AL 3,353,595

UNDERWATER WELL COMPLET I ONS Filed May 22. 1964 5 Sheets-Sheet 5 min.

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INVENTORS Afro/71v: VJ

United States Patent Ofilice 3,353,595 Patented Nov. 21, 1967 3,353,595 UNDERWATER WELL COMPLETIONS Bobby H. Nelson, David L. Gruller, and Leonard E. Williams, Houston, Tex., assignors to Cameron Iron Works, Inc., a corporation of Texas Filed May 22, 1964, Ser. No. 369,500 30 Claims. (Cl. 166-.6)

This invention relates generally to the completion of oil and gas wells. In particular, it relates to improvements in the method of and apparatus for completing an olfshore well in which the wellhead is located at an underwater level.

In the completion of wells of this type, after setting a conductor casing having a base structure on its upper end at the underwater level, the surface casing is run into the well through the conductor casing and a casing head secured to its upper end is connected to the upper end of the conductor casing and base structure. Pressure control equipment is then lowered onto the upper end of the easing head by means of a guide system extending between the underwater level and the water level. This system often includes a series of spaced-apart cables anchored at their lower ends to the base structure and suspended at their upper ends from the vessel from which drilling operations are conducted.

In some applications, the pressure control equipment includes a riser pipe which is connected above one or more blowout preventers for extension upwardly to water level. In this case, the desired number of inner casings may be run through it and each suspended from the casing head by means of a casing hanger laudable in the head while maintaining pressure control over the well. When the last casing has been run and hung 01f, production tubing is run into the well within the innermost casing and suspended therein by means of a tubing hanger supported within the casing head and preferably on the hanger for such casing. With the pressure control equiprnent removed, a Christmas tree installed above the tubing hanger provides control over production from the tubing.

This production is conducted from the Christmas tree to flowliness which extend from a flowline head at one side of the Christmas tree along the underwater level to a suitable place of disposal, usually some distance from the well site. Thus, it is necessary, during the completion process, to connect the Christmas tree with the flowline head which has been guidably lowered into an anchored position on the underwater base by the same guide cables on which the riser pipe is lowered. This connection is made from a remote location at the water level.

Even when the well is to produce from only a single zone, there may be two or more tubings suspended from the tubing hanger in order to facilitate the running of various tools into and out of the well. Obviously therefore, a corresponding number of flow passages through the tubing hanger, the Christmas tree above the tubing hanger, and the flowline head must be sealably interconnected. Thus, the aforementioned connection must not only take into account the lateral distance between the Christmas treeand the flowline head, but also the position of the flow passages in the Christmas tree with respect to those in the flowline head in a rotational sense as well as the axial alignment of the various flow passages. That is, it is necessary that the Christmas tree and thus the tubing hanger be so oriented with respect to the casing head as to disposed each flow passage therein for remote connection with a corresponding flow passage of the flowline head.

The need for orienting the tubing hanger in a rotational sense also occurs in the completion of multiple zone wells on land, even though there is no problem in remotely connecting the Christmas tree flow passages with the flowlines. Thus, in the case of land completions wherein the various wellhead parts such as the tubing head and Christmas tree are connected by bolted flanges, the rotational orientation of the tubing hanger with respect to the tubing head on which it is to be supported must be' predetermined in order that the flow passages in the Christmas tree and tubing hanger will be aligned for sealed interconnection when the tree flange is bolted to the tubing head flange.

In this latter case, alignment has been accomplished by means of cooperating lugs and grooves on the tubing hanger and some permanent portion of the wellhead, such as the bore of the tubing head in which the hanger is to be landed. The proximity of the latter alignment part to the upper end of the blowout preventer stack above the tubing head permits the operator to align both parts fairly closely as the hanger is landed, so that the tubing hanger need be further guided through only a few degrees of rotation for precise alignment. Thus, the camming surfaces for guiding the tubing hanger require but little height and, consequently, the use of such a system does not require a taller tubing head than would otherwise be used.

Also, when the tubing hanger has a shoulder to be landed on a seat within the bore of the tubing head, the portion of such bore above the seat as well as the bore of the blowout preventer thereabove are in any case large enough to pass the shoulder. Thus, the lugs or groove on the head for orienting the corresponding part on the tubing hanger lowered through this enlarged bore does not increase the inner diameter requirements of this equipment.

This simple lug and groove arrangement has not, however, provided a ready solution to the problem of orienting a tubing hanger in the completion of an olfshore well in which the wellhead is located at the underwater level. Thus, when the tubing hanger must be lowered several hundred feet or more from the water level to the casing head, there is no easy way to approximate its orientation as it approaches landed position. In fact, the tubing hanger may be so far from its oriented position that only wide guide surfaces on both sides of the groove would insure its ultimate disposal over the lug. This would require a more expensive wellhead not only from the standpoint of its necessarily greater height, but also due to the necessity of leaving the specially fabricated part on the wellhead at the underwater level.

In offshore well completions of this type, the tubing hanger is preferably supported on the casing hanger for the innermost casing string so that the bore through the casing head need be no larger in diameter than the easing hangers which are run through it in the suspension of the casing strings. Therefore, whether the lug be located on the tubing hanger or on the well-head bore, the latter would have to be enlarged in the case of an underwater well completion to permit the above-described lug and groove to interfit as the hanger is landed. The correspondingly larger bore of the pressure control equipment would require that such equipment have considerably greater strength capacity for holding pressure over a larger cross sectional area, and that it therefore be much more expensive than necessary.

It is understandable, therefore, that prior underwater completion techniques have turned in a different direction, and, more particularly, have adopted the practice of guidably lowering the tubing hanger with the Christmas tree by means of parts on the tree cooperable with the aforementioned guide cables. Since the flowline head is guidably lowered into place in the same way, the plural flow passages in each of such head and the tubing hanger, and thus those of the Christmas tree connected to the hanger, are automatically oriented into the desired posi- 3 tions relative to one another so that the subsequent connection between the tree and flowline head may be made.

However, since the guide cables are outside of the pressure control equipment, such equipment must first be removed from above the casing head so that the Christmas tree may be connected with the cables. This has several shortcomings since the well is not under pressure control at this stage of the completion process. Similarly, in the event the tubing hanger is raised when the well is reworked, pressure control over the well is again sacrificed.

More particularly, in accordance with these practices, and after removal of the pressure control equipment, the tubing is first lowered on the tubing hanger to spear it into the inner casing and the tubing hanger is then raised to water level for connection with the Christmas tree. This is necessary since, when landed, the tubing hanger will be within the casing head, so that only the tree is free for connection to the guide cables. At this time, the tubing hanger with the tubing suspended therefrom and having its lower end speared into the inner casing is lowered with the tree for landing on the casing head. This presents a further problem inasmuch as there is no convenient way to test the seal between the tubing hanger and the portion of the casing head in which it is landed until after the Christmas tree has been run. Thus, in the event the seal does not hold, it is necessary to pull the Christmas tree as well as the tubing hinger.

An object of this invention is to provide a method of and apparatus for completing or reworking a well of this type in which pressure control may be maintained over it during running or pulling of the tubing.

Another object is to provide a method of and apparatus for completing a well of this type in which the seal between the tubing hanger and the portion of the casing hanger on which it is to he landed may be tested prior to installation of the Christmas tree thereabove.

A further object is to provide a method and apparatus of the character above described which does not require a casing head of greater than ordinary height or diameter.

Still another object is to provide a method and apparatus of the character above described which does not require that the casing head be oriented about its axis than that required by prior practices.

A still further object is to provide a method and apparatus of the character above described which does not require that the casing head be oriented above its axis in a predetermined manner with respect to the flowline head, and thus permits the casing head to be connected to the conductor casing by simple means.

Still a further object is to provide a method which may be performed simply and quickly and apparatus for accomplishing this method which is inexpensive to manufacture.

These and other objects are accomplished, in accordance with the illustrated embodiment of the invention, by apparatus which permits the tubing hanger and tubing suspended from it to be lowered through the pressure control equipment and landed in the casing head separately of the Christmas tree. That is, as will be described to follow, there is a means on the hanger engageable with means on the bore of the pressure control equipment to orient the tubing hanger into a desired rotational position as it is so lowered. More particularly, the tubing hanger is so oriented that when the Christmas tree is connected above it with the flow passages in the tree accurately aligned with those of the tubing hanger, the Christmas tree flow passages will be properly oriented for connection with the flow passages of the flowline head.

Thus, during this stage of the completion process, control over the well pressure may be maintained. Also, a seal :between the tubing hanger and the casing head may be tested and the hanger and seal pulled for adjustment, if desired, prior to installation of the tree.

, After running and landing of the tubing hanger and testing of its seal, the pressure control equipment is released from the casing head andraised to water level. The Christmas tree is then attached to the guide system and lowered onto the upper end of the casing head above the tubing hanger. When the guide system includes cables of the type previously described, the flow passages of the tree will be at least reasonably well oriented in a rotational sense and axially aligned with respect to those of the tubing hanger as the tree is lowered onto the head. However, these fiow passages must be sealably connected to one another, as by means of nipples which extend from one for telescoping within the other. Therefore, there are additional parts on the tree and hanger, and to be described in detail to follow, which orient and accurately align these passages as the tree lands on the casing head.

The tubing hanger is oriented with respect to the casing head by a lug on one of the tubing hanger and bore through the pressure control equipment and a groove on the other for closely receiving the lug. Cam surfaces taper upwardly from each side of the groove for intersection with one another and the lower end of the lug is pointed so as to guide the lug into the groove. Thus, the hanger will move down into properly oriented position regardless of the relative positions of the lug and groove as they first engage. That is, there are no horizontal surfaces on which the lug might rest and prevent continued downward movement of the hanger.

As previously indicated, in the illustrated embodiment of the invention, this orienting means includes a part formed on the lower end of the pressure control equipment. This is preferred since it permits the orienting means to be removed from beneath the water level upon completion of the well so that it may be used at other locations. Still further, the height of bore necessary to accommodate the part and the cam guide surfaces need not be added to the casing head, but rather to the pressure control equipment in which the extra height is no problem.

In accordance with a further preferred form of the invention, and as shown in the illustrated embodiment thereof, the bore through the pressure control equipment is of approximately the same diameter as that of the casing head so as to provide a continuation thereof. A hollow bushing is lowered into the bore of the control equipment and located in a desired rotational position by means of a spring-pressed lug adapted to fit in a longitudinally extending groove in such bore. The aforementioned lug and groove together with cam surfaces for orienting the tubing hanger into the desired rotational position are formed on the tubing hanger and bushing so that, as the hanger is lowered through the bushing for landing on the casing head, it will cooperate with the bushing so as to be oriented into a desired rotational position with respect to the bushing and thus with respect to the aligned bores of the pressure control equipment and casing head. Upon landing of the tubing hanger, the bushing may be removed upwardly through the bore of the pressure control equipment preparatory to installation of the Christmas tree.

The flow passages of the Christmas tree are accurately aligned with respect to the flow passages of the oriented tubing hanger in both an axial as well as a rotational sense. For this purpose, there is an internal cylindrical surface on the lower end of the Christmas tree which is fittable closely over an external cylindrical surface on the upper end of the tubing hanger as the Christmas tree moves downwardly onto the casing head along the aforementioned guide system. There are also cooperating parts on the Christmas tree and tubing hanger for orienting the tree into a more accurate rotational postion with respect to the tubing hanger as such tree is guided axially with respect to the tubing hanger. These latter parts, which may also include a lug and a longitudinal groove together with cam surfaces for receiving the lug, insure that the nipples suspended from the Christmas tree will fit closely into the flow passages of the tubing hanger during the final phase of downward movement of the Christmas tree.

Preferably, the part on the tubing hanger for orienting it with respect to the hollow bushing as well as the part thereon for orienting the Christmas tree comprises a single lug on the outer side of such tubing hanger. Thus, it will be understood that when the tubing hanger has been landed, and the hollow bushing is moved upwardly from about the tubing hanger, such lug thereon will be exposed so that the groove on the Christmas tree is free to move over it.

In the drawings, wherein like reference characters are used throughout to designate like parts;

FIG. 1 is a view, partly in elevation and partly in section, of the upper end of an offshore well of the type described including a casing head connected to the upper end of a conductor casing and the lower end of pressure control equipment lowered onto the upper end of the casing head by means of a guide system including a plurality of cables anchored at their lower ends to the base structure about the conductor casing;

FIG. 2 is a cross-sectional view of the equipment shown in FIG. 1, as seen along broken line 22 of FIG. 1;

FIG. 3 is an enlarged half-sectional view of the upper end of the casing head and lower end of the pressure control equipment shown in FIG. 1, together with the means for connecting the two from a remote location at the water level;

FIG. 4 is a full sectional view of the upper end of the casing head and lower end of the pressure control equipment of FIG. 1, and illustrating the step of the abovedescribed process in which the hollow bushing has been lowered into and located in the bore of the pressure control equipment;

FIG. 5 is a full sectional view similar to FIG. 4, but showing a further step in the method wherein the tubing hanger has been lowered through the bushing and oriented into a desired rotational position as it lands upon the casing hanger for the innermost casing string;

FIG. 6 is a 360 degree development of the groove and cam surfaces on the inside of the bushing of FIGS. 4 and 5;

FIG. 7 is another full sectional view similar to FIGS. 4 and 5, but illustrating another step in the method in which the bushing and pressure control equipment have been removed from the upper end of the casing head;

FIG. 8 is a view similar to FIG. 7, but illustrating a further step in the method in which the Christmas tree has been lowered onto the casing head above the tubing hanger and accurately aligned with respect to said hanger so as to dispose the lower ends of seal nipples carried by its plural flow passages within the plural flow passages of the tubing hanger;

FIG. 8A is a detailed sectional view of the parts on the tree and tubing hanger for aligning said tree, as seen along broken line 8A-8A of FIG. 8;

FIG. 9 is a cross-sectional view of the tubing hanger and Christmas tree, as seen along broken line 99 of FIG. 8; and

FIG. 10 is an elevational view of the completed wellhead including the Christmas tree shown in FIG. 9 and a fiowline head anchored with respect to the base to one side of the Christmas tree, together with a U-shaped pipe lowered into place to connect the upper end of the tree with the upper end of the fiowline head.

With reference now to the details of the above-described drawings, the upper end of the well shown in FIG. 1 includes a conductor casing 20 which has been lowered to a desired depth within a relatively large hole 21 drilled into the underwater level 22. A base structure 23 is secured about the upper end of the conductor casing 20 and at the underwater level 22. The conductor casing has been anchored within the hole 21 by means of cement 6 about a substantial portion of its length, and usually all the way to the surface, as indicated at 24.

There are a plurality of conical anchors 25 on the top side of the base structure 23 for attachment to the lower ends of cables 26 which extend upwardly to water level for attachment to the drilling vessel. As shown in FIG. 2, there are preferably three equally spaced-apart anchors and cables, each of which is located at a corner of the triangularly shaped frame 23.

There is also a support 27 anchored to the base structure 23 and extending upwardly therefrom to one side of the conductor casing, as shown diagrammatically in FIGS. 1 and 2. As shown in FIG. 10, this support mounts the upper end of a fiowline head 113 at substantially the same level as the upper end of a Christmas tree which is to form the uppermost part of the completed wellhead. This fiowline head is lowered onto the support 27 with the aid of the guide system, and is connected to flowlines 113a which extend downwardly to the underwater level and outwardly from the base structure to either a land surface or to a gathering station at some remote location. Thus, as previously mentioned, the fiowline head 113 is located in a predetermined position with respect to the conductor casing, and thus the wellhead parts to be mounted thereon, both insofar as the lateral distance between the centerline of the wellhead and the centerline of the fiowline head is concerned as well as the rotational orientation of the fiowline head about the axis of the conductor casing is concerned.

As shown in FIG. 1, a casing head 28 has been lowered onto and connected with the upper end of the conductor casing 20 by means of J-slots 29 about a flange 30 connected to the casing head by means of spaced-apart guide wings 33. These slots are fitted over pins 31 extending outwardly from the upper end of the conductor casing for attaching in an obvious manner. As can be seen from FIGS. 1 and 2, these wings serve to guide the casing head into the conductor casing 20 and thereby align the flange 30 for fitting over the upper end thereof.

As shown in FIG. 1, a string of surface casing 34 is connected to the lower end of the bore 28a through the casing head 28 for extension downwardly within the conductor casing 20. Pressure control equipment 35 is connected to the upper end of the casing head for extension upwardly therefrom to the water level (not shown). It includes, from its lower end on up, a remotely actuated connector 36, one or more blowout preventers 37 and a riser pipe 38.

As will be described more fully hereinafter, and as best shown in FIGS. 3 to 5, the connector 36 has a bore 39 therethrough which forms a continuation of the upper enlarged end of the bore 28a of the casing head. The upper end of the connector 36 is, in turn, connected to the lower end of blowout preventer 37 by bolts 40 (see FIG. 1) extending through the adjacent flanges of these two members, and the preventer also has a bore 41 therethrough which forms a continuation of the casing head bore 28a and connector bore 39. The upper end of the blowout preventer is connected to the lower end of the riser pipe 38 by means of any suitable coupling 42, and the bore 43 through this riser pipe provides a. still further continuation of the casing head bore as well as the bores through the connector and blowout preventer.

After the surface casing 34 has been run with the casing head 28 and the casing head connected to the conductor casing 20, the surface casing is cemented in place, with the returns being taken up through the annulus between surface casing and conductor casing. The abovedescribed pressure control equipment 35 is then guidably lowered onto the casing head by means of guide sleeves 44 which are connected to the body of the connector 36 by means of radially extending arms 45 having holes 45a therein to receive lines 45b which may be let out or taken up from the water level. As shown in the sectional portion of FIG.,1 as well as in FIG. 2, each guide sleeve passes freely over one of the guide cables 26 so as to at least approximately align and orient the control equipment in a rotational sense.

When the lower end of the pressure control equipment 35 approaches engagement with the upper end of the casing head, flared lower ends 46 on the sleeves 44 will fit closely over the upwardly tapered sides of the anchors 25 on the base structure 23. Thus, during this final stage of its lowering, and just as it lands upon the upper end of the casing head, the pressure control equipment will be axially aligned and rotatably oriented in a more accurate manner.

With particular reference to FIG. 3, the connector 36 includes a main body 47 through which the bore 39 extends and flanges 48 and 49 on each end of the body. The lower flange 48 rests upon a'similar flange 50 on the upper end of casing head 28, and the two flanges are coupled together by means of spaced-apart dogs 51 carried on the flange 48. The joint between the flanges 48 and 50 is sealed by means of an annular gasket 52 carried by the lower end of the inside of the flange 48 and fitting tightly with respect to tapered surfaces on the inner diameters of the flanges 48 and 50.

The dogs 51 are movable between the locking position of FIG. 3 and an unlocking position in which their lower inside surfaces are free to move upwardly or downwardly over the outer end of the flange St). For this purpose, the dogs are surrounded by a ring 53 carried on the lower end of a series of pistons 54 each of which is sealably slidable within one of a series of cylinder 55. Thus, with reference to FIG. 3, when the pistons are moved downwardly, the inner tapered surface of the ring 53 will slide downwardly over the outer tapered surfaces of the dogs 51 to swing them in a clockwise direction and into coupling position. On the other hand, when the ring 53 is moved upwardly, it will engage an outwardly extending flange 56 on the upper ends of the dogs to swing them in a counterclockwise direction and out of locking position beneath the flange 50.

As is shown in FIG. 3, the stern 54a of each piston 54 is enclosed by a sheath 57. Also, each piston and its cylinder provides an assembly which is removably fittable within an opening 58 in an outwardly extending flange on the connector body 47, and locked therein by means of bolts 59 through a flange on the upper end of the cylinder. A skirt 60 extends downwardly from the outer end of the connector body flange to protect the piston and cylinder assemblies as well as the dogs 51 in the operation of the connector.

The above-described connector will be found to be similar in many respects to that shown and described in US. Patent No. 3,096,999. It is remotely operable from water level by means of hydraulic fluid which is admitted to and exhausted from the cylinders on opposite sides of the pistons 54. Thus, in the use of the connector at the lower end of the pressure control equipment 35, the pistons 54 are moved upwardly so as to cause ring 53 to retract the dogs 51 from locking position. In this manner, the tapered inside surfaces on the lower ends of the dogs will guide the lower end of the pressure control equipment in moving downwardly into engagement with the upper end of the casing head 28. Then, when the flange 48 is seated on the flange 55, the piston 54 and thus the ring 53 may be moved downwardly so as to force the lower ends of the dogs inwardly beneath the casing head flange 50, and thereby releasably connect the lower end of the pressure control equipment to the upper end of the casing head.

When the pressure control equipment has been connected above the casing head, as above described, one or more strings of easing are run therethrough and suspended from the casing head 28. In the well illustrated, there is an intermediate string 61 within surface casing 34 and an oil string 62 within the intermediate string. The firstmentioned string is suspended from a casing hanger 63 seated upon a tapered shoulder 64 in the bore 28a of the casing head beneath the upper enlarged portion thereof. As best shown, for example, in FIG. 4, this hanger includes a body 65 threadedly connected to the upper end of the casing 61 and a seal assembly 66 closing off the annular space between the upper end of the body and the bore 28a of the casing head. In these and other respects, it may be similar in construction and operation to that shown and described in a copending patent application, executed May 6, 1964 by Bobby H. Nelson and Leonard E. Williams, and entitled Well Apparatus, and assigned to the assignee of the present application. Thus, as described in this copending application, there may be one or more openings through the casing hanger body 65 to permit cement returns to be taken upwardly through the annulus between the casing suspended by the hanger and the next outer casing. After the casing has been cemented in place, the seal assembly is lowered into the position shown in the drawings and then looked to the upper end of the casing hanger body about which it is disposed.

The oil string 62 is suspended from a casing hanger 67 which may be substantially identical in construction and operation to the casing hanger 63. Thus, it includes a body 68 having a downwardly tapered seat 69 for landing upon an upwardly tapering seat 70 on the upper end of seal assembly 66 of the casing hanger 63. As in the case of easing hanger body 65, the hanger body 68 is threadedly connected to the upper end of the casing string 62 which is hung from it. Also, body 68 may have one or more holes therethrough which are closed, after cementing of the string 62 in place, by means of seal assembly 71 forming part of the casing hanger and lowered onto and connected with the upper end of easing hanger body 68.

For this latter purpose, and as can be seen from the drawings, the seal assembly 71 provides a seal between the body 68 and the bore 28a of the casing head. In addition, this assembly may also carry parts for holding the casing hanger 67, and thus the casing hanger 63 upon which hanger 67 rests, down within the casing head. For example, this assembly 71 may carry slips which are automatically urged into hold-down position by actuation of the seal assembly in the manner described in the aforementioned pending patent application.

Obviously, other casing hanger construction may be used in running and hanging off the casing strings within the casing head 28. In any case, however, the casing hangers are of such construction as to permit them to be run through the bore of the pressure control equipment and into landed positions within the casing head, whereby the well pressure may be kept under control at this stage of the completion process. Also, they are preferably nested so that the bore of the casing head need not be enlarged above the seat 64.

As shown in FIGS. 4 and 5, there is a longitudinally extending groove 72 in the bore of the lower end of the connector 36 of the pressure control equipment 35. This groove is adapted to closely receive a lug 73 which is carried within a recess 73a on the outer periphery of a hollow bushing 74 which fits closely within the bores of the connector and blowout preventer. More particularly, the dog is urged radially outwardly from the outer periphery of bushing 74 by means of a spring 75 carried between the inner side of the dog and the recess 73a of the bushing, such urging being limited by pins 75a in the recess. Thus, as the bushing is run through the pressure control equipment by means of a running tool 76 (see FIG. 4), the dog 73 will be pressed inwardly so as to be in substantial alignment with the inner periphery of the pressure control equipment. However, when the lug reaches the level of the groove 72, and is rotated into a position in which it is opposite the groove, the lug will snap into the groove so as to locate the bushing in a desired rotational sense.

When the bushing has been so located, its lower end 77 will seat upon the upper end 78 of the seal assembly 71 of easing hanger 67. Actually, this landing of the lower end of the bushing on the casing hanger will enable the operator at water level to determine that the bushing 74 has reached the desired position and that it may be rotated so as to cause the dog to engage in the groove 72. As can be seen from FIGS. 4 and 5, the bore 74a through the bushing is at least as large as the bore through the upper end of easing hanger 67 so as to receive the tubing hanger in a manner to be described hereinafter.

As best shown in FIG. 4, there is a longitudinally extending groove 79 on the bore 74a of the lower end of the hollow bushing. Also, and as previously described, there are cam surfaces 80 which taper upwardly from each opposite side of the upper end of the groove 79 to a point of intersection 81 which, when the tapers are at the same angle, is disposed diametrically opposite the center of the groove 79. The upper end of the bushing includes an annular recess 32 having threads 83 thereabout for connecting with the lower threaded end of running tool 76.

When the bushing has been run and located in the manner described, the running tool 76 is removed therefrom and tubing hanger 84 is lowered on a suitable running tool (not shown) through the pressure control equipment and bushing into the position shown in 'FIG. 5 in which a downwardly tapering shoulder 86 thereon seats upon an upwardly tapering shoulder or seat on the inner side of the seal assembly 71 of easing hanger 67. With the tubing so landed, a pair of tubing strings 84a and 8412 connected to the lower ends of flow passages 84c and 84d therethrough are suspended within the oil string 62. There are threads 84c and 84] about the upper ends of the flow passages to receive removable back pressure valves and/or to connect with the aforementioned running tool.

When so landed, the tubing hanger is sealed with respect to the casing hanger by means of one or more seal rings 87 carried about its downwardly tapering shoulder 86. Also, the tubing hanger is locked down within the casing hanger by means of dogs 88 carried about the body 90 of the hanger above the seat 86 thereon and adapted to be moved outwardly into locking position within a recess 92 in the seal assembly 71 of easing hanger 67 by means of pistons 89 longitudinally slidable with respect to a body 90 of the hanger.

Thus, as shown in FIG. 5, there is a pressure chamber 91 intermediate oppositely facing shoulders on the piston 89 and body 90 of the tubing hanger to receive hydraulic fluid for forcing the piston downwardly to move the dogs from a first position in which they are retracted with respect to the hanger to the locking position shown in FIG. 5. As will be appreciated from FIG. 5, in its upper position, piston 89 permits the dogs to move inwardly of the bore through the upper end of casing hanger 67 so that the tubing hanger may be lowered therethrough. Although the details of same are not important, it will further be understood that upon release of pressure fluid from within the chamber 91, the piston 89 is free to move upwardly, whereby an upward pull on the tubing hanger will cause the downwardly tapering shoulder on the upper side of locking dog recess 92 to bear against a complementary shoulder on the upper ends of the dogs 88. Thus, the dogs are cammed inwardly to free the tubing hanger for withdrawal. If desired, of course, the hydraulic actuator maybe constructed to act in both directions so as to positively move the piston 89 upwardly as well as downwardly.

As shown in FIG. 5, there is a lug 94 at the upper end of the body 90 of tubing hanger 84 for fitting closely within the longitudinal groove 79 in bushing 74. As previously described, the close fit of this lug within such groove will orient the passages -84c and 84d in the tubing hanger into a desired rotational position. That is, since the pressure control equipment 35 is lowered onto the casing head by means of the same guide cables 26 which are used for guidably lowering the fiowline head onto the base structure 23, and further since the bushing 74 is fixedly located in a rotational sense with respect to the groove 72 in the lower end of the pressure control equipment, the disposal of lug 94 in groove 79 will thereby predetermine the position of tubing hanger flow passages 84c and 84d with respect to the flow passages in the fiowline head.

As previously described, as the tubing hanger 84 is lowered through the pressure control equipment, the lug 94 thereon will most probably be disposed out of axial alignment with the bushing groove 79. Thus, as illustrated by the broken lines of FIG. 6, the lower end of the lug will ordinarily first engage the bushing along one of the cam surfaces 80. However, due to the fact that the lower end of the lug is pointed and that the cam surfaces extend entirely about the bore of the bushing 84a, the tubing hanger will continue to move downwardly after this initial engagement of the lug until the lug is axially aligned with the groove 79. At this time, the lug moves downwardly within the groove 79 so as to finally orient the tubing hanger in the desired rotational sense.

It will be noted, in this respect, that the relatively close fit of the piston 89 within the upper bore of the casing hanger 67 will align the tubing hanger with respect to the axis of the bore through the wellhead prior to fitting of the lug within the groove 79. More particularly, the tubing hanger is guided into the upper bore of easing hanger 67 by tapered seat 87 on the lower end thereof. That is, as can be seen from FIGS. 4 and 5, this tapered seat will initially engage with an inner taper on the upper end of seal assembly 71 of easing hanger 67 since the tubing hanger fits rather loosely within the bushing 74 as it is lowered through it.

When the tubing hanger has thus been oriented, landed and locked in place, the eifectiveness of the seal 37 may be tested. For this purpose, the flow passages 84c and 84d are plugged and the rams (not shown) of the blowout preventer 37 are closed so as to form a pressure chamber within the bore and above the seal 37. At this time, test fluid may be introduced from the water level into the pressure chamber by means of the kill line (not shown) of the blowout preventer. If the seal does not hold pressure, the tubing hanger may be withdrawn upon opening of the blowout preventer rams. On the other hand, if the seal does hold, the operator may proceed with the completion of the well.

In this latter event, the running tool '76 or its equivalent is lowered to engage with the upper end of bushing 74, and the bushing is then pulled from the well through the pressure control equipment. In this respect, it will be noted that the groove 79 on the inner side of the bushing extends all the way through the lower end of the bushing so that the latter is free to move upwardly from the tubing hanger lug 94. Also, of course, as the bushing is pulled upwardly, the spring-pressed dog 73 will be urged inwardly so that it will ride upwardly along the bore through the pressure control equipment.

Upon pulling of the bushing 74, the pressure control equipment 35 is removed from above the casing head 28, as illustrated in FIG. 7. That is, as will be obvious from the foregoing description, pressure fiuid is admitted to the cylinders 55 of the connector 36 beneath the pistons 54 therein so as to raise the ring 53 and thereby swing the lower end of the dogs 51 out of locking position beneath the casing head flange 50. This frees the dogs to be raised past the flange 56, whereby the pressure control equipment may be lifted from above the casing head guided by the guide cables 26. As shown in FIG. 7, with the pressure control equipment so removed, the upper end of the casing hanger 67 will project upwardly from the flange 50 at the upper end of the casing head, and the upper end of tubing hanger 84 will project upwardly from the upper end of the casing hanger. More particularly, the lug 94 on the upper end of the tubing hanger will be exposed above casing hanger 67 for cooperation with the Christmas tree in a manner to be described.

As illustrated in FIGS. 8 and 10, and as previously described, the Well is completed by the lowering of a Christmas tree 95 onto the tubing hanger 84 and the connection of the lower end of such Christmas tree with the upper end of the casing head 28. More particularly, as the Christmas tree is so lowered, the flow passages 95:: and 95b therethrough are accurately aligned with respect to the flow passages 84c and 84d, respectively, of the tubing hanger, whereby the flow passages in the Christmas tree are, similarly to the flow passages in the tubing hanger, oriented into a desired rotational sense and axially aligned with respect to the bore of the wellhead for connection with corresponding passages of the fiowline head 113.

Since the flow passages are accurately aligned, tubular nipples 96 and 97 threadedly connected to and depending from the lower ends of flow passages 95a and 52), respectively, will fit closely Within the upper ends of tubing hanger flow passages 84c and 34d to provide a sealed connection therebetween. Obviously, this alignment must be accurate in order to prevent damage to the nipples, and especially the seal rings 98 about their lower ends which fit within the tubing hanger fiow passages.

These nipples 96 and $7 extend downwardly within a connector 99 coupled to the lower end of the master valves of the Christmas tree by means of bolts 1% extending between the adjacent flanges 101 and 1552 of the connector body and the master valve body. This connector may be similar in construction to the connector 36 previously described so as to provide a remotely operable and releasable connection for the tree to the upper end of the easing head as the tree is guidably lowered onto the position shown in FIGS. 8 and 10.

For this latter purpose, the connector 99 includes a connector body 103 having a flange 1% on its lower end for seating on the casing head flange 5t) and dogs 195 carried by the flange 104- for swinging between locking and unlocking positions by means of apparatus similar to that described in connection with connector 36. As was also true in the case of connector 36, a gasket 105 is carried Within a tapered recess on the lower end of connector body 13 to form a seal with respect to another tapered recess on the inner end of the encasing head flange 50. Still further, there are arms M7 which extend outwardly from a skirt 188 about the body 103 of the connector, and sleeves 1&9 are disposed on the outer ends of the arms 167 for guidably sliding over the guide cables 26. As previously described, this insures that the flow passages through the Christmas tree will be at least approximately aligned with respect to those of the tubing hanger as the Christmas tree is lowered into place.

As shown in FIG. 8, the connector body 103 has an upper cylindrical bore 110 and a concentrically arranged enlarged cylindrical bore 111 beneath the bore 110. The upper bore 110 fits closely over the upwardly extending cylindrical portion of the upper end of the body of tubing hanger 84, while the lower bore 111 fits relatively closely about the upwardly extending cylindrical portion of the casing hanger 67. As also shown in FIG. 8, as well as in FIG. 9, there is a longitudinal groove 112 in the lower end of the bore 119 of the connector body 163 for fitting closely over the lug 94 on the tubing hanger 84. As shown in FIG. 8A, there are cam surfaces 112a on each opposite side of the lower end of groove 112 for guiding the groove onto the lug $4. Thus, as the Christmas tree approaches its landed position, it will not only be guided in an axial sense, but also will be oriented into a desired rotational position by the fitting of this groove over the lug 94. More particularly, the above-described parts for aligning the flow passages axially and orienting them in a rotational sense are effective prior to the movement of the lower ends of tubular nipples as and 97 into the upper ends of tubing hanger flow passages 84c and 84d.

When the Christmas tree has been so landed and connected to the upper end of the casing head with its flow passages sealably connected to the flow passages in the tubing hanger, the running tool for same (not shown) may be removed from a neck about its upper end, and the flow passages therethrough connected to the corresponding flow passages through the fiowline head 113. As previously described, this fiowline head has been lowered onto and releasably connected with the flowline head support 27 with the aid of the guide cables 26. With the fiowline head landed and supported on the support 27, a neck 114 having flow passages at the upper end thereof will be at substantially the same level as the neck 115 on the upper end of the Christmas tree 95. The upper ends of these fiowline head flow passages are, of course, oriented and axially aligned with those through the Christmas tree. Thus they may be interconnected by a U tube 116 or the like having corresponding passages therethrough, guidably lowered onto the heads by the guide system.

This U tube 116 may be similar in construction and operation to that described in copending application Ser. No. 130,387, filed August 9, 1961, by Arthur G. Ahlstone, entitled Well Completion Apparatus, and assigned to the assignee of the present application. Thus, its opposite ends are releasably connected to the necks 114 and 115 on the flowline head and Christmas tree, respectively, by any suitable remotely coupling mechanism, such as that described in the above mentioned copending application. Since the U tube 116 is lowered by means of the same guide system, the coupling mechanisms on its opposite ends will be suificiently well aligned with the necks of the Christmas tree and flowline so that the remote connection may be made without difficulty.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the method and apparatus.

It will be understood that certain features and sub-combinations are of utility and may be employed without reference to other features and subcornbinations. This is contemplated by and is within the scope of the claims.

As many possible embodiments may be made of the invention Without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

The invention having been described, what is claimed 1. In a method of completing an offshore well including a casing head disposed at an underwater level, a guide system extending downwardly from the water level to the underwater level, and pressure control equipment releasably connected in a predetermined rotational position to the upper end of the casing head; the steps of lowering a tubing hanger having plural flow passages therethrough and tubing suspended from the passages through the control equipment, engaging the hanger with means on the pressure control equipment, as said tubing hanger is so lowered, to orient said tubing hanger into a desired rotational position within the casing head and landing it in such position, releasing the control equipment from the upper end of the casing head and raising it to water level, connecting a Christmas tree having plural flow passages therethrough to the guide system, and lowering the tree onto the upper end of the casing head and the tubing hanger with its flow passages accurately aligned with and sealed to the flow passages of the tubing hanger.

2. In a method of completing an offshore well including a casing head disposed at an underwater level, a guide system extending downwardly from the water level to the underwater level, and pressure control equipment removably connected in a predetermined rotational position to the upper end of the casing head; the steps of lowering a tubing hanger having plural fiow passages therethrough and tubing suspended from the passages through the control equipment and engaging said tubing hanger with means within the control equipment as the tubing hanger is so lowered for orienting said tubing hanger into a desired rotational position with respect to the casing head, landing said tubing hanger in the casing head in said desired rotational position,-removing said control equipment and said orienting means therein from the upper end of the casing head and raising it to water level, connecting a Christmas tree having plural flow passages to the guide system, lowering the tree by means of the guide system onto the upper end of the casing head, and engaging said tree with means on the tubing hanger as it is so lowered for accurately aligning the passages therethrough with the passages of the tubing hanger.

3. In a method of completing an offshore well including a casing head disposed at an underwtaer level, a guide system extending downwardly from the water level to the underwater level, and pressure control equipment releasa- .b1y connected in a predetermined rotational position to the upper end of the casing head, the bore through the pressure control equipment being of approximately the same diameter as the bore through the casing head; the steps of lowering a hollow bushing through the control equipment and locating it in a fixed rotational position with respect to the bore of the control equipment, lowering a tubing hanger having plural flow passages therethrough and tubing suspended from the passages through the control equipment and bushing and engaging the tubing hanger with the bushing as it is so lowered for orienting said hanger into a desired rotational position with respect to the casing head, landing the tubing hanger within the casing head in said desired rotational position, removing the bushing upwardly from within the control equipment, releasing the control equipment from the upper end of the casing head and raising it to water level, connecting a Christmas tree having plural flow passages therethrough to the guide system, and lowering the tree onto the upper end of the casing head and tubing hanger with its flow passages accurately aligned with the flow passages of the tubing hanger.

'4. For use in the completion of an offshore well including a casing head at an underwater level having a bore therethrough, pressure control equipment releasably connected in a predetermined rotational position to the upper end of the casing head, and a guide system disposed externally of the casing head and extending between water level and the underwater level; a tubing hanger having plural flow passages therethrough with means for suspending tubing from the passages, means on the tubing hanger for lowering it through the control equipment into a landed position within the casing head, means on the control equipment for orienting the tubing hanger into a desired rotational position with respect to the casing head as the hanger isso lowered, a Christmas tree having plural flow passages therethrough and means thereon cooperable with the guide systemv for lowering it onto the upper end of the casing head above thetubing hanger 'upon release and removal of the control equipment and means for accurately aligning the flow passages through the tree with the tubing hanger flow passages as the tree is so lowered.

"5. Olfshore wellhead apparatus, comprising a casing head having'a bore therethrough for disposal at an under- Water level, pressure control equipment having means on its lower end for releasably connecting it in a predeter mined rotational position to the upper end of the casing head with the bore through the control equipment aligned withthe' bore through the casing head, a tubing hanger having plural flow passages therethrough and lowerable through the control equipment into a landed position within the casing head, and meansincluding a part on the tubinghanger cooperable with a part in the bore of said control equipment as the hanger is so lowered to orient 'the hanger "into a desired rotational position with respect" to said head when landed therein.

6. Offshore wellhead apparatus of the character defined in claim 5, including a Christmas tree having plural flow passages therethrough and lowerable onto the upper end of the casing head for connection thereto above the tubing hanger upon release and removal of the control equipment, and means for accurately aligning the flow passages on the tree and hanger as the tree is so lowered.

7. An offshore wellhead assembly, comprising a casing head having a bore therethrough for disposal at an underwater level, pressure control equipment having means on its lower end for releasably connecting it in a predetermined rotational position to the upper end of the casing head with the bore through the control equipment aligned with the bore through the casing head, a tubing hanger having plural flow passages therethrough and lowerable through the control equipment into a landed position within the casing head, and means including parts on the tubing hanger and in the bore of one of the casing head and control equipment for engagement with one another, as the hanger is so lowered, to orient the hanger into a desired rotational position with respect to the head when landed therein, one of said parts including a lug and the other a longitudinally extending groove to closely receive the lug and cam surfaces tapering from each side of the groove for intersection with one another.

8. Ofishore wellhead apparatus, comprising a casing head having a bore therethrough for disposal at an under- 'water level, pressure control equipment having a bore therethrough of approximately the same diameter as the casing head bore and means on its lower end for releasably connecting it in a predetermined rotational position to the upper end of the casing head and with the bores therethrough arranged coaxially, a longitudinally extending groove on the bore of one of said control equipment and easing head, a tubing hanger having plural flow passages therethrough and adapted to be lowered through the control equipment into a landed position within the casing head, and means including a lug for fitting within the groove to orient the hanger into a desired rotational position with respect to the casing head as it is so lowered, said lug being spring-pressed to permit it to be rotated into the groove and to be moved vertically through the bore of the pressure control equipment.

9. Ofishore wellhead apparatus of the character defined in claim 8 including a Christmas tree having plural flow passages therethrough and lowerable onto the upper end of the casing head above the tubing hanger for connection thereto upon release and removal of the control equipment, and means for accurately aligning the flow passages through the tree and hanger as the tree is so lowered.

10. Offshore wellhead apparatus of the character defined in claim 8, wherein the groove is on the bore of the control equipment.

11. An offshore wellhead assembly, comprising a casing head having a bore therethrough for disposal at an underwater level, pressure control equipment having a bore of approximately the same diameter as the casing head bore and means on its lower end for releasably connecting it in a predetermined rotational position to the upper end of the casing head and with the bores arranged coaxially, a longitudinally extending groove on the bore of one of said control equipment and casing head, a hollow bushing lowerable through the control equipment and having a spring-pressed lug for fitting within the groove when so lowered, a tubing hanger having plural fio'w passages therethrough and adapted to be lowered through the control equipment and bushing into a landed position within the casing head, and means on the hanger and bushing for orienting the hanger into a desired rotational position with respect to the casing head as it is so lowered into landed position.

12. An offshore wellhead assembly of the character defined in claim 11, wherein the groove is formed in the control equipment.

13. An offshore wellhead assembly of the character defined in claim 11, wherein the orienting means comprises a longitudinal groove on one of the hanger and bushing, and a rigid lug on the other of the hanger and bushing for fitting within the groove.

14. Offshore wellhead apparatus for use with a casing head having a bore therethrough disposed at an underwater level, comprising pressure control equipment having a bore therethrough and means on its lower end for releasably connecting it in a predetermined rotational position to the upper end of the casing head with the bore therethrough axially aligned with the bore through the casing head, a tubing hanger having plural fiow passages therethrough and adapted to be lowered through the control equipment into a landed position within the casing head, means for orienting the hanger into a desired rotational position with respect to the head, a Christmas tree having plural flow passages therethrough and means thereon for guidably lowering it onto the upper end of the casing head above the tubing hanger when the control equipment is released and removed therefrom and means on the tree and tubing hanger for accurately aligning the flow passages therethrough as the tree is so lowered.

15. Offshore wellhead apparatus of the character defined in claim 14, wherein said last-mentioned means includes a cylindrical surface on the tree closely fittable over a cylindrical surface on the tubing hanger, a lug on one of said tree and tubing hanger, and a longitudinal groove in the other of the tree and tubing hanger for closely receiving the lug as the tree is so lowered.

16. Offshore wellhead apparatus of the character defined in claim 14, wherein the hanger orienting means comprises a part on the tubing hanger engageable with a part in the bore of said pressure control equipment as the tubing hanger is so lowered.

17. Offshore wellhead apparatus, comprising a casing head having a bore therethrough and disposable at an underwater level, pressure control equipment having means on its lower end for releasable connection in a predetermined rotational position to the upper end of the easing head with the bore through the pressure control equipment axially aligned with the bore through the casing head, a tubing hanger having plural flow passages therethrough and adapted to be lowered through the pressure control equipment into a landed position within the casing head, means providing a longitudinal groove in the bore of one of said casing head and pressure control equipment, a lug on the tubing hanger fittable within the groove for orienting the hanger into a desired rotational position as it is so lowered, a Christmas tree having plural flow passages therethrough and means thereon for guidably lowering it onto the upper end of the casing head above the tubing hanger when the connector is released and removed therefrom, and means including a longitudinal groove on the tree fittable over the lug on the tubing hanger for accurately aligning the passages therethrough as the tree is so lowered.

18. An offshore wellhead assembly, comprising pressure control equipment having a bore therethrough and means on its lower end for connecting it in a predetermined rotational position to the upper end of a casing head, a longitudinally extending groove on the bore of the pressure control equipment, a hollow bushing lowerable into and rotatable within said bore and having a spring-pressed dog on the outer side thereof for disposal within the groove to locate the bushing in a desired rotational position within the body, and means on the bushing for orienting a tubing hanger into a desired rotational position as the tubing hanger is lowered through the pressure control equipment and bushing into a landed position in said casing head.

19. An offshore wellhead assembly of the character defined in claim 18, wherein said orienting means includes a lug on the tubing hanger and longitudinally extending 16 groove on the bushing to receive the lug and a camming surface tapering upwardly from each side of the groove.

20. For use with an offshore wellhead assembly, pressure control equipment having a bore therethrough and connecting means on its lower end, and means within the bore of the pressure control equipment providing a longitudinal groove and camming surfaces tapering upwardly from opposite sides of the groove.

21. An offshore wellhead assembly, comprising pressure control equipment having a bore therethrough and connecting means on its lower end, means within the bore of the pressure control equipment providing a longitudinal groove, a tubing hanger lowerable into said bore, and a lug on the tubing hanger movable into the groove as the tubing hanger is so lowered to orient the tubing hanger into a desired rotational position with respect to said pressure control equipment.

22. An offshore wellhead assembly, comprising pressure control equipment having a bore therethrough and connecting means on its lower end, a longitudinal groove on the bore, a tubing hanger lowerable into the bore, and means including a spring-pressed lug disposable within said groove for orienting the tubing hanger into a desired rotational position with respect to said pressure control equipment as the tubing hanger is so lowered.

23. For use with an offshore wellhead assembly, a hollow bushing, a spring-pressed lug on the outer side of the bushing, a tubing hanger lowerable into a closely fitting position within the bore of the bushing, a longitudinally extending groove in one of said hanger and the bore of the bushing, and a rigid lug on the other of the hanger and bore of the bushing disposable within the groove as the hanger is so lowered to orient the hanger into a desired rotational position within the bushing.

24. For use with an offshore wellhead assembly, a hollow bushing having connecting means on the upper end, a longitudinal groove on the bore of the bushing, camming surfaces tapering upwardly from opposite sides of the groove, a lug on the outer side of the bushing, and spring means normally urging the lug from the outer side of the bushing but being compressible inwardly to permit the lug to move inwardly to provide a substantial continuation of said outer side.

25. For use with an offshore wellhead assembly, a tubing hanger having plural flow passages therethrough, a Christmas tree having plural flow passages therethrough adapted to be sealably connected with the tubing hanger passages as the tree is lowered over said tubing hanger,

and a lug. on one and a longitudinal groove on the other of said hanger and tree for orienting the tree into a desired rotational position with respect to the hanger as said tree is so lowered, said hanger having a cylindrical portion at its upper end and said Christmas tree having a cylindrical portion at its lower end for fitting closely over the cylindrical portion of the hanger so as to axially align the passages as the tree is so oriented.

26. As in 25, wherein said lug is on the cylindrical portion of the hanger and said groove is on the cylindrical portion of said tree.

27. For use with an offshore wellhead assembly,a hollow bushing having a longitudinal groove on its bore, a tubing hanger having plural flow passages therethrough and lowerable into the bushing, a lug on the hanger to fit within the groove for orienting the hanger in a rotational sense as the hanger is so lowered, a Christmas tree having plural flow passages therethrough and lowerable onto the tubing hanger, and means including a longitudinal groove on the tree fittable over the hanger lug for accurately aligning the tree passages with the hanger passages as the tree is so lowered.

28. For use in the completion of an offshore well including a casing head at an underwater level having a bore therethrough and a guide system extending between water level and the underwater level; apparatus comprising a first wellhead member having a plurality of longitudinal flow passages therethrough and lowerable into connection with said casing head, means for orienting the first Wellhead member into a desired rotational position with respect to the casing head as it is so lowered, a second wellhead member having a plurality of longitudinal flow passages therethrough, means on the second wellhead member cooperable with the guide system for lowering it onto said first member, said first member having a cylindrical portion and said second member having a cylindrical portion for fitting telescopically with respect to the cylindrical portion of said first member as it is lowered thereon, and means on the cylindrical portions of said first and second members for orienting the second member into a desired rotational position as the cylindrical portion of the second member telescopes with respect to the cylindrical portion of the first so as to align the flow passages in said members with one another.

29. Apparatus of the character defined in claim 28, wherein one of said wellhead members has a tubular extension from one of its flow passages for fitting closely within the aligned flow passage of the other wellhead member, and said means for orienting the first and second Wellhead members relative to one another comprises a groove in one and a lug on the other for entering the groove before said tubular extension fits within said aligned flow passage.

30. In a method of completing an offshore well including a casing head disposed at an underwater level and pressure control equipment releasably connected in a predetermined rotational position to the upper end of the casing head, wherein the bore through the pressure control equipment is of approximately the same diameter as the bore through the casing head; the steps of lowering a casing hanger having casing suspended therefrom through the control equipment and casing head into a landed position within said casing head, lowering a hollow bushing having substantially the same outer diameter as the casing hanger through the control equipment and locating it above the casing hanger in a fixed rotational position with respect to the bore of the control equipment, lowering a tubing hanger having plural flow passages therethrough and tubing suspended from the passages through the control equipment and hollow bushing, engaging the tubing hanger with the bushing as it is so lowered for orienting said tubing hanger into a desired rotational position with respect to the casing head, and landing the tubing hanger within the casing head in said desired rotational position.

References Cited UNITED STATES PATENTS CHARLES E. OCONNELL, Primary Examiner. R. E. FAVREAU, Assistant Examiner. 

1. IN A METHOD OF COMPLETING AN OFFSHORE WELL INCLUDING A CASING HEAD DISPOSED AT AN UNDERWATER LEVEL, A GUIDE SYSTEM EXTENDING DOWNWARDLY FROM THE WATER LEVEL TO THE UNDERWATER LEVEL, AND PRESSURE CONTROL EQUIPMENT RELEASABLY CONNECTED IN A PREDETERMINED ROTATIONAL POSITION TO THE UPPER END OF THE CASING HEAD; THE STEPS OF LOWERING A TUBING HANGER HAVING PLURAL FLOW PASSAGES THERETHROUGH AND TUBING SUSPENDED FROM THE PASSAGES THROUGH THE CONTROL EQUIPMENT, ENGAGING THE HANGER WITH MEANS ON THE PRESSURE CONTROL EQUIPMENT, AS SAID TUBING HANGER IS SO LOWERED, TO ORIENT SAID TUBING HANGER INTO A DESIRED ROTATIONAL POSITION WITHIN THE CASING HEAD AND LANDING IT IN SUCH POSITION, RELEASING THE CONTROL EQUIPMENT FROM THE 